Angiotensin III (Ang III) is a heptapeptide agonist at the angiotensin 1 (AT1) and AT2 receptors, with a 30-fold higher affinity for AT2 compared with AT1 in HEK293 cells.1,2 Ang III is the preferred agonist for renal AT2 receptors, which are responsible for sodium excretion into the urine.3 Ang III induces the same level of aldosterone synthesis as Ang II but has lower vasoconstrictive activity in vivo.4 In the brain renin-angiotensin system, Ang III increases sympathetic nerve activity and vasopressin release and dampens the baroreflex leading to higher blood pressure.5
1.Bosnyak, S., Jones, E.S., Christopoulos, A., et al.Relative affinity of angiotensin peptides and novel ligands at AT1 and AT2 receptorsClin. Sci. (Lond.)121(7)297-303(2011) 2.Wright, J.W., and Harding, J.W.Brain renin-angiotensin--a new look at an old systemProg. Neurobiol.95(1)49-67(2011) 3.Kemp, B.A., Bell, J.F., Rottkamp, D.M., et al.Intrarenal angiotensin III is the predominant agonist for proximal tubule angiotensin type 2 receptorsHypertension60(2)387-395(2012) 4.Blair-West, J.R., Coghlan, J.P., Denton, D.A., et al.A dose-response comparison of the actions of angiotensin II and angiotensin III in sheepJ. Endocrinol.87(3)409-417(1980) 5.Gao, J., Marc, Y., Iturrioz, X., et al.A new strategy for treating hypertension by blocking the activity of the brain renin-angiotensin system with aminopeptidase A inhibitorsClin. Sci. (Lond.)127(3)135-148(2014)